Method for removably connecting two members and connection systems for realizing the same

ABSTRACT

A method for creating a releasable joint between two components wherein one of the components is elastically deformed by radial compressive forces in such a way that one effective circumferential contour corresponds to the corresponding effective circumferential contour of the other component with a predefined clearance, and the two components are fitted together. After being fitted together, a compressive joint is created by the fact that the deformed component is elastically deformed back by reducing or discontinuing the radial compressive forces. What is used as the elastically deformable component is a hollow body which has multiple cavities in its wall, and the radial compressive forces are exerted on the inner or outer contour of the hollow body located opposite the effective circumferential contour in such a way that their working lines, considered in the circumferential direction, run approximately centeredly through the cavities.

FIELD OF THE INVENTION

The present invention concerns a method for creating a releasable jointbetween two components, in which one of the components is elasticallydeformed by radial compressive forces in such a way that one effectivecircumferential contour corresponds to the corresponding effectivecircumferential contour of the other component with a predefinedclearance, so that the two components can be inserted into one another;and in which, after the two components have been fitted together, acompressive joint is created by the fact that the deformed component iselastically deformed back by reducing or discontinuing the radialcompressive force.

BACKGROUND OF THE INVENTION

Methods of this kind for creating a frictionally engaged joint betweentwo components are known from DE 195 21 755 C1 and from DE 196 24 048A1. With these methods, a polygonal or oval component is elasticallybrought in identical fashion into a round shape by the application ofradial compressive forces, so that a round shaft can be installed whilethe radial compressive forces are maintained. When the radial forces arethen reduced or discontinued, the deformed component springs back intoits original oval or polygonal shape, so that the shaft is immobilizedtherein by way of a press fit. This manner of joining two components hasproven entirely successful in practice. It is nevertheless oftenconsidered disadvantageous that extremely large compressive forces arenecessary if the component to be deformed possess large wallthicknesses, and the deformations which occur can then also not bemanaged precisely, i.e. are to some extent undefined.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to describe a method and ajoining system of the kind cited initially with which thesedisadvantages can be overcome, i.e. which allow the easy utilization ofcomponents to be deformed that have a large wall thickness.

According to the present invention, this object is achieved in that whatis used as the elastically deformable component is a hollow body thathas multiple cavities in its wall; and that the radial compressiveforces are exerted on the inner or outer contour of the hollow bodylocated opposite the effective circumferential contour in such a waythat their working lines, considered in the circumferential direction,run approximately centeredly through the cavities. It has been foundthat the cavities exhibit the deformation behavior of thin-walledcomponents, and can be deformed with comparable energy expenditure, iftheir cross section is weakened in accordance with the present inventionby cavities, and the radial deformation forces act in the region of thecavities.

According to an embodiment of the invention, provision is made for thehollow body used to be one whose cavities are closed toward theeffective circumferential contour, the effective circumferential contourhaving, in the undeformed state, circumferential segments lying insideand outside the effective circumferential contour of the othercomponent. For example, if a shaft is to be clamped from outside, thehollow body used is one whose cavities are provided in the region ofthose circumferential segments which, in the unclamped state, lieoutside the circumferential contour of the shaft that is to be clamped,and the radial compressive forces are exerted on the cavities fromoutside. The result is that the regions of the hollow body lying betweenthe force application points—i.e. those circumferential segments thatlie, in the unclamped state, inside the circumferential contour of theshaft—are pushed outward, so that the shaft can be inserted into thehollow body.

If the hollow body is to be used to clamp a hollow shaft on the outside,the hollow body used is one whose cavities are provided in the region ofthose circumferential segments that lie, in the unclamped state, insidethe circumferential contour of the other component, and the radialcompressive forces are applied onto the hollow body from the inner side.The result of this is that the circumferential segments placed betweenthe force application points, are drawn inwardly so that the hollow bodycan be inserted into the hollow shaft.

A further embodiment provides for using, as the elastically deformablecomponent, a hollow body that has multiple recesses extending in thecircumferential direction which, viewed in the circumferentialdirection, arc open in their center region toward the effectivecircumferential contour that comes into contact with the othercomponent; and that the radial compressive forces are exerted on theinner or outer contour of the hollow body that lies opposite theeffective circumferential contour in such a way that their working lineslie inside the opening regions of the recesses toward the effectivecircumferential contour, so that the body segments formed between the,opening regions are moved by the deformation substantially radially intothe region of the recesses in this case, if radial compressive forcesare exerted on the hollow body in the regions where the recesses opentoward the effective circumferential contour, the result is that thebody segments lying therebetween, at which the effective circumferentialcontour is constituted, are pulled radially into the region of therecesses, thereby achieving the clearance necessary for fitting togetherthe two components.

For example, if a shaft is to be clamped from outside, what is used is ahollow body in the form, for example, of an annular element in which therecesses open toward the inner circumference; and radial compressiveforces are exerted on the hollow body from outside. The result of thisis that the regions of the hollow body lying between the forceapplication points are pushed outward, thus also causing the bodysegments to be moved outward substantially without deformation, so thatthe shaft can be inserted into the hollow body. The recesses—which forexample can be introduced into the hollow body by way of anelectrodischarge machining operation—must possess a width in the radialdirection such that the body segments have sufficient room to deflect,and can be configured, for example, in the form of radial slits orslots.

Because the effective circumferential contour of the deformablecomponent is substantially the same in the loaded and unloaded states,particular machining operations in the manufacture of said component arenot necessary. For clamping a round shaft, for example, all that isnecessary is to create on the hollow body a round inner contour whoseradius for producing the press fit is somewhat smaller than that of theshaft, i.e. in the unclamped state the inner contour lies completelyinside the circumferential contour of the shaft that is to be clamped.

If a [hollow shaft is to be clamped externally with the] hollow body isto be clamped inside a hollow shaft, the recesses open toward the outercircumference of the hollow body and the radial compressive forces areapplied onto the hollow body from the inner side. The result of this isthat the body segments that are formed between the opening regions arepulled inward into the region of the recesses, so that the hollow bodycan be inserted into the hollow shaft. In this case as well, the radialmovement of the body segments takes place substantially withoutdeformation of the external effective circumferential contour, whichcorrespondingly has, in the unclamped state, a circular shape whosediameter is somewhat greater than the inside diameter of the hollowshaft.

The cavities should extend over a substantial circumferential region ofthe hollow body. It has proven to be advantageous if they extendaltogether over at least 2000, in particular over approximately 2800 to3000, so that they are separated from one another only by narrow webregions. According to a preferred embodiment, a total of three recessesare provided in the hollow body, each extending over a circumferentialregion of 80 to 1000; preferably they are arranged uniformly distributedover the circumference.

Regarding further advantageous embodiments of the invention, referenceis made to the dependent claims and to the description below of anexemplary embodiment referring to the appended drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of a joining system according to thepresent invention for clamping a shaft, in the clamped state;

FIG. 2 shows the joining system of FIG. 1 in the fitting and/or releasedstate;

FIG. 3 shows a second embodiment of a joining system according to thepresent invention for clamping a shaft, in the clamped state;

FIG. 4 shows the joining system of FIG. 3 in the fitting and/or releasedstate;

FIG. 5 shows a third embodiment of a joining system according to thepresent invention for clamping a shaft, in the clamped state;

FIG. 6 shows the joining system of FIG. 5 in the fitting and/or releasedstate,

FIG. 7 shows the deformable component of a further embodiment of ajoining system configured according to the present invention forexternal clamping of workpieces, in the unloaded state; and

FIG. 8 shows the deformable component of FIG. 7 in the loaded state.

DETAILED DESCRIPTION

FIGS. 1 and 2 depict an embodiment of a joining system 1 configuredaccording to the present invention. This joining system 1 comprises around shaft (not depicted) and a hollow body, in the form of an annularelement 2, to be fastened onto the shaft. Annular element 2 has apolygonal inner contour and an approximately circular outer contour, theouter contour on the one hand having circumferential segments 3 a thatlie within the outer circumference of the shaft, and on the other handpossessing circumferential segments 3 b that lie outside the outercircumference of the shaft. The polygonal shape is provided for athree-point clamping; for two-point clamping, the inner contour can beof oval configuration. Annular element 2 has three approximately kidneyshaped cavities 4 which each extend over a circumferential region ofapproximately 1000 and are introduced into hollow body 2 by, forexample, an electrodischarge machining or milling operation.

To create a joint between the shaft and annular element 2, radialcompressive forces F are exerted on annular element 2 from outside, theforce application points being selected so that the working lines offorces F run approximately centeredly through cavities 4. As a result ofcompressive forces F, annular element 2 is pressed radially inward inthe region of the force application points, and at the same time theregions located centeredly between the force application points—i.e.those circumferential segments 3 a that, in the unclamped state, lieinside the outer contour of the shaft and thus prevent insertion of theshaft into annular element 2—are elastically deformed radially outward,so that the inner contour assumes a round shape as depicted in FIG. 2.The radial movement of circumferential segments 3 a creates the spacethat is necessary so that the shaft can be inserted into annular element2 or pulled back out of hollow body 2.

When the radial compressive forces are then reduced or discontinued.annular element 2 deforms elastically back again, with the result thatcircumferential segments 3 a move back inward again and press with theelastic return force against the inner wall of the shaft, thus forming apress fit.

If a [hollow shaft is to be clamped externally with the] hollow body isto be clamped inside a hollow shaft, the recesses open toward the outercircumference of the hollow body and the radial compressive forces areapplied onto the hollow body from the inner side. The result of this isthat the body segments that arc formed between the opening regions arepulled inward into the region of the recesses, so that the hollow bodycan be inserted into the hollow shaft. In this case as well, the radialmovement of the body segments takes place substantially withoutdeformation of the external effective circumferential contour, whichcorrespondingly has, in the unclamped state, a circular shape whosediameter is somewhat greater than the inside diameter of the hollowshaft.

FIGS. 3 and 4 depict a second embodiment of a joining system configuredaccording to the present invention. This joining system comprises around shaft 1 and a hollow body, in the form of an annular element 2,fastened on shaft 1. Annular element 2 has a circular inner and outercontour, the diameter of the inner contour being slightly less than thediameter of shaft 1, i.e. the inner contour lies entirely within theouter contour of shaft 1. Annular element 2 has three cavities in theform of groove-like recesses 4, which each extend over a circumferentialregion of approximately 100° and are open toward the inner circumferenceof annular element 2, so that only narrow web regions 3 remain betweenthem.

To release—or conversely—to create—the joint depicted in FIG. 2[1]between shaft 10[1] and annular element 2, radial compressive forces Fare exerted on annular element 2 from outside, the force applicationpoints being selected so that the working lines of forces F runapproximately centeredly through the opening regions of recesses 4. As aresult of compressive forces F, annular element 2 is elasticallydeformed radially inward in the region of the force application points,and at the same time radially outward in the circumferential regionslocated approximately centeredly between the force application points,in which web regions 3 also lie. Annular segments 2 a, 2 b, 2 c arethereby also moved radially outward—for which recesses 4 allow thenecessary space—but are deformed only insignificantly or not at all. Asa result of the radial movement of annular segments 2 a, 2 b, 2 c, theireffective inner contours release from shaft 10[1] so that the latter canbe pulled out of annular element 2.

FIGS. 5 and 6 depict a third embodiment of a joining system according tothe present invention which has the same basic configuration as thejoining system explained above and depicted in FIGS. 1 and 2. All thatis different is the configuration of recesses 4, which in the secondembodiment are configured as comparatively narrow slots which extendalong the center diameter of annular element 2 and open toward the innercontour by way of three radial groove-like slits 5 that each proceedcenteredly, viewed in the circumferential direction, radially inwardfrom recesses 4 and correspondingly have an angular offset of 120° fromone another.

This results in the formation of three annular segments 2 a, 2 b, 2 c,which are each delimited in the circumferential direction by two ofslits 5 and toward the outside by recesses 4, and are joined to theremaining annular elements 2 by web regions 3 located between recesses4. Recesses 4 and radial slits 5 can be electrodischarge machined orotherwise introduced into annular element 2.

FIGS. 7 and 8 depict a hollow body, configured as an annular element 2,of a further joining system according to the present invention withwhich a hollow body (not depicted), for example a hollow shaft, can beexternally clamped. As in the case of the first exemplary embodiment,annular element 2 has recesses 4 that each extend over approximately1000 in the circumferential direction along the center radius of annularelement 2, so that narrow web regions 3 remain between them. A slit 5extends radially outward from each recess 4; the slits proceed, whenviewed in the circumferential direction, approximately centeredly fromrecesses 4, so that they each have an angular offset of 1200 from oneanother. The outer circumference of annular clement 2 is selected sothat it is somewhat smaller than the inner circumference of theworkpiece that is to be clamped. When annular element 2 is then to beimmobilized in the workpiece, compressive forces F are exerted, asindicated in FIG. 6, on annular element 2 on the inner circumferenceengaging in such a way that their working lines F run approximatelycenteredly through slits 5. As a result of the radial compressive forcesF, annular element 2 is deformed outward on the inner circumference inthe region of the force application points, for which recesses 5 leavethe necessary space, and at the same time the annular element iselastically deformed inward approximately centeredly between the forceapplication points so that annular segments 2 a, 2 b, 2 c are pulledinward, for which recesses 4 also offer the necessary room (FIG. 8).

Since no direct forces act on annular segments 2 a, 2 b, 2 c, theyexperience only a radial movement but otherwise essentially nodeformation; recesses 5 and slits 5 simply become somewhat smaller. Theapplication of force thus decreases the outside diameter of annularelement 2 so that it can be inserted into the workpiece that is to beclamped when the radial compressive forces are then reduced ordiscontinued, annular element 2 elastically deforms back, with theconsequence that its diameter increases again and annular segments 2 a,2 b, 2 c push with the elastic return force against the inner wall ofthe workpiece, thus forming a press fit.

What is claimed is:
 1. A method for creating a releasable joint betweentwo components, in which one of the components is elastically deformedby radial compressive forces in such a way that its effective innercircumferential contour corresponds to an effective outercircumferential contour of the other component with a predefinedclearance, so that the two components can be inserted one into the otherthereby fitting them together; and in which, after the two componentshave been fitted together, a compressive joint is created by the factthat the deformed component is elastically deformed back by reducing ordiscontinuing the radial compressive forces, the method comprising thesteps of providing a hollow body as the elastically deformable componenthaving multiple cavities in its wall; and exerting the radialcompressive forces on one effective circumferential contour of thehollow body located opposite the effective inner circumferential contourin such a way that working lines of the radial compressive forces,considered in the circumferential direction, run approximatelycenteredly through the cavities.
 2. The method as defined in claim 1,wherein the radial compressive forces are exerted on the hollow body ina manner uniformly distributed over the outer circumference.
 3. Themethod as defined in claim 1, wherein the hollow body used is one whosecavities are closed toward the effective inner circumferential contour,the effective inner circumferential contour having, in the undeformedstate, circumferential segments lying inside and outside the effectiveouter circumferential contour of the other component.
 4. The method asdefined in claim 3, wherein the hollow body used is one whose effectiveinner circumferential contour has a polygonal or oval basic shape. 5.The method as defined in claim 3, wherein the hollow body used is onewhose cavities are provided in the region of those circumferentialsegments which lie, in the unclamped state, outside the outercircumferential contour of the shaft that is to be clamped.
 6. Themethod as defined in claim 1, wherein what is used as the elasticallydeformable component is a hollow body that has multiple cavitiesextending in the circumferential direction which, viewed in thecircumferential direction, are open in their center region toward theeffective inner circumferential contour; and the radial compressiveforces are exerted on the outer contour of the hollow body that liesopposite the effective inner circumferential contour in such a way thatthe working lines of the radial compressive forces lie in the openingregions of the cavities toward the effective inner circumferentialcontour, and thus the body segments formed between the opening regionsare moved by the deformation substantially radially.
 7. The method asdefined in claim 6, wherein what is used is a hollow body whoseeffective inner contour lies, in the unclamped state, entirely insidethe outer circumferential contour of the shaft that is to be clamped. 8.A joining system having first and second components to be joined, inwhich the first component is elastically deformable by radialcompressive forces in such a way that its effective innercircumferential contour corresponds to the corresponding effective outercircumferential contour of the second component with a predefinedclearance, so that the second component can be inserted into the firstcomponent thereby fitting them together; and in which, after the firstand second components have been fitted together, a compressive joint iscreated by the fact that the first component is elastically deformedback by reducing or discontinuing the radial compressive forces, whereinthe elastically deformable component is a hollow body that has multiplecavities in its wall extending over at least 200° in the circumferentialdirection and separated from one another only by narrow web regions. 9.The joining system as defined in claim 8, wherein the hollow body hasthree cavities which each extend over a circumferential region of 80 to100° and are arranged uniformly distributed over the circumference ofthe hollow body.
 10. The joining system as defined in claim 8 whereinsaid cavities extend over approximately 200° to 300° in thecircumferential direction and are separated from one another only bynarrow web regions.